Apparatus or furnace for hardening steel cutters or other tools.



- No. 769,052. PATENTED AUG. 30, 1904.

' s. IN.'BRAYISHAW.

APPARATUS OR FURNACE FORJHARDENING STEEL GUTTERS OR OTHER TOOL S.

APPLIOATION FILED APR.26,1904. no MODEL 2 snnms snzm 1.

A No. 769,052.

I PATENTED AUG. 30, 1904. s. N. BRAYsHA'W.

. APPARATUS 0 FURNACE FOR HARDENING STEELVGUTTERS OR OTHER TOOLS.

APPLIOATION FILED APR. 26, 1904.

no MODEL. 2 SHEETS-SHEET 2.

UNITED STATES Patented August so, 1904.

PATENT OFFICE.

APPARATUS 0R FURNACE FOB HARDENING STEEL CUTTERS OR OTHER TOOLS.

SPECIFICATION forming part of Letters Patent No. 7 69,052, dated August 30, 1904.

Application filed April Z6, 190A.

To all whom it may concern: 7

Be it known that I, SHIPLEY NEAVE BRAY- sHA'W, a subject of the King of Great Britain, and a resident of Manchester, in the county of Lancaster, England, have invented certain new and useful Improvements in Apparatus or Furnaces for Hardening Steel Cutters or other Tools or Articles, of which the following is a specification.

This invention isdesigned to provide an improved arrangement or construction of furnace for heating cutters or other tools or 'articles in a melt-pot containing a fusible salt or metal for the purpose of hardening them.

Hitherto it has-been customary to have'an .open pot to contain the fusible salt, and it was practically impossible to obtain uniform resuits, and greatloss was occasioned by inequality in heating the tool orarticles, more particularly when of large size.

' The invention is' characterized by a meltpot to contain the fusible-salt and receive the tools to be hardened, wholly inclosed in an annular casing, with a tray also inside the casing upon which the articles are placed to be immersed in the melt-pot and a ring of gasburners to apply heat to the melt-pot to raise it to and maintain it at thedesired temperathe melt-pot B. The casing is open below at a supported on suitable supports 0 to admit sufiicient air for the purposes of combustion.

A melt-pot B is placed in the interior of the annular casing A, the casing extending up above-the pot and being inclosed by a lid or .door B in the top of the casing. Around the bottomof the casing a number of gas or oil jets or burners D are placed. These are placed beneath the inwardly inclined or projecting Serial No. 205,051. (to model.)

part a" of the casing A, so as to be protected fromany splashes of molten material that may i fall from the melt-pot B. Inside the ring of .burners is placed a stand or pedestal E, of firebrick or other suitable material, upon which the melt-pot B stands; The pedestal E becomes hot by the flames from the burners impinging upon it, and below it is a tray or receptacle F to catch'any drops or splashes of molten material that may fall from the melt-pot. In the front or.side of the furnacecasing a vertically-sliding door G is fitted, preferably balanced by a counterweight, like a damper, and from the opposite side or from two sides aflue or flues H project to carry off the waste products of combustion and fumes from the melt-pot B. A tray K is placed inside the furnace, with one or two or more supporting or guide rods 76, which pass through the lid B, being suspended from a chain balanced by a counterweight. The tray is perforated with a number of small holes 7c and formed with a larger hole, through which a pyrometer P passes into the melt-pot, which tray K is used to agitate the fusible salt in the pot and to lower the cutters or articles to b heated into the pot.

The cover B of the casing A is preferably in two parts to permit of the insertion of the tray to carry the articles to be heated. The meltepot B may be made of cast-iron or other suitable materialand is filled or partially filled, preferably, with a salt fusible at the required temperature of less specific gravity than steel,

though an easily-fusible metal or alloy may be employed.

A suitable fusible salt may be prepared from an admixture of potassium carbonate, sodium carbonate, sodium chlorid, and yellow ferrocyanid of potassium invsuitable proportions, such as the following: 'KzCOs, six parts; Na2CO3, six parts; NaCl, twelve parts; I{AFQG(CN), one part.

What I claim as my. invention, and desire to protect by Letters Patent, is

l.'Apparatus for hardening steel cutters and other tools comprising in its construction an annular casing with inwardly-projecting sides, a melt-pot therein wholly inclosed by the casing to contain a fusible mixture, a perforated tray inside the furnace to hold the tools andlower them into the pot, a pedestal of fire-brick upon which the pot rests and against which the flame impinges and a ring of burners placed round the bottom of the furnace substantially as described.

2. In apparatus for hardening steel cutters and other tools the combination with an annular furnace easing A providedwith inwardly-projecting sides, a melt-pot B placed therein wholly inclosed by the casing, a lid B to cover in the melt-pot, a plurality of burners D at the bottom of the furnace to heat the SHIPLEY N. BRAYSHAW.

Witnesses:

J. OwDnN OBRIEN, B. ABRAM VVooDmaAD. 

